Convertible burner

ABSTRACT

A burner has a first chamber with ports for a first gas and a second chamber with ports for a second gas. Facilities selectively connect the chambers to a gas supply conduit.

United States Patent [1 1 [111 3,801,259 Hendrick Apr. 2, 1974 1 1 CONVERTIBLE BURNER 2,750,997 6/1956 Reulcr 431/284 2,748,848 6/1956 Fl nn 431/284 [75] Fred Remind" Long Beach 3,754,853 8/1973 Briiucksiek et a1. 431 225 Calif,

[73] Assignee: Robertshaw Controls Company,

Richmond Primary ExammerEdward G. Favors Attorney, Agent, or Firm-Anthony A. OBnen [22] Filed: June 18, 1973 [21] Appl. No.2 370,991

{57] ABSTRACT [52] US. Cl 431/285, 431/80, 431/347 [51] Int. Cl. F23g 9/00 A burner has a first chamber with ports for a first gas [58] Field Of Search 431/284, 285, 80, 347 and a second chamber with ports for a second gas Fa- Y cilities selectively connect the chambers to a gas sup- [56] References Cited ply conduit.

UNITED STATES PATENTS 1,461,663 7/1923 Kemmer 4311284 20 Claims, 6 Drawing Figures PATENIEUAPR 2 I974 FIG. i

PATENIEHAPR' 21914 33301." 259 SHEET 2 BF 2 FIG. 3

CONVERTIBLE BURNER BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to burners, and in particular, to burners convertible for operation by different fuels. In certain applications, such as in mobile homes, it is desirable to have burners which can be alternately connected to different fuel supplies, such as propane or natural gas supplies.

2. Description of the Prior Art Prior art gas burners have been converted for use with different fuels by changing, removing or inserting burner orifice members to make the burner compatible for the type of fuel being used. However, such convertible burners are generally of the aerated type having a single burner orifice where the conversion can be readily made. For burners of the non-aerated type employing a plurality of burner orifices, such conversion of burner orifice members, is difficult and expensive to make.

Additionally the prior art, as exemplified by U.S. Pat. Nos. 1,938,355, 2,344,936, 2,840,152 and 3,164,200, includes several burners which can be converted for alternate use by gaseous fuel and liquid fuel oil; generally, such burners employ separate burner facilities mounted in close relationship for burning gas and liquid without any cooperation between the separate facilities except forimounting structure, valve controllers and flame space. Liquid fuel oil burners are generally not readily adaptable for burning gaseous fuels such as natural gas or propane gas.

SUMMARY OF THE INVENTION The invention is summarizedin that a burner selectively adaptable for operation by a first fuel and a second fuel includes a burner member containing a first chamber and a second chamber with a wall between the first and second chambers, input means for communicating from a supply passageway to the first and second chambers, the input means being capable of selectively communicating from the supply passageway to the first chamber, the burner member having a first burner port from the first chamber and a second burner port in the wall exiting into the first chamber from the second chamber, the first burner port being designed to produce streams of the first fuel for sustaining a flame, and the second burner port being designed to produce streams of the second fuel from the first burner port for sustaining a flame.

An object of the invention is to construct a burner which is easily convertible for operation by different fuels.

Another object is to provide a convertible burner of the non-aerated type.

An advantage of the invention is that a burner can be converted for use with either a low-heat-generatingcapacity gaseous fuel, or a high-h'eat-generatingcapacity gaseous fuel.

Additional features of the invention include the provision of first and second burner ports which are aligned wherein a stream of fuel from the first burner port exits through the second burner port; the provision of a first input opening through a wall between a first chamber and a second chamber and a second input opening into the first chamber wherein the first and second openings are aligned and facilitiescommunicate through the second input opening with the first input opening to the exclusion of the first chamber; the provision of inner and outer coaxial annular chambers with circumferentially spaced ports from the inner chamber exiting through the outer chamber and respective circumferentially spaced ports from the outer chamber; and the provision of three coaxial tubular sections joined to form a dual chamber burner member.

Other objects, advantages and features of the invention will become apparent from the following description of the preferred embodiments taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is elevation view in cross section of a burner apparatus constructed in accordance with the invention and illustrating a first mode of operation.

FIG. 2 is a view similar to FIG. 1 but illustrating the burner apparatus in. a second mode of operation.

FIG. 3 is a cross section view of a first modification of input facilities to a broken away portion of a burner member of the burner apparatus of FIG. 1 in a first mode of operation.

FIG. 4 is a cross section view of a broken away portion of the first modification in FIG. 3 illustrating a second mode of operation.

FIG. 5 is a cross section view of a second modification-of input facilities connected to broken away portions of input tubes of the modification in FIG. 3 in a first mode of operation.

FIG. 6 is a view similar to FIG. 5 but illustrating the second modification in a second mode of operation.

DESCRIPTION OF THE PREFERRED EMBODIMENT As illustrated in FIGS. 1 and 2, the present invention is embodied in a fuel burner apparatus having a burner member indicated generally at 10, input facilities indicated generally at 11, and a flame sensing element 68. The input facilities 11 are convertible for selecting the mode of operation of the burner member 10 by a supply of a high-heat-generating'capacity-per-unit volume fuel, or alternately, by a supply of a low-heatgenerating-capacity-per-unit-volume fuel. The highheat-generating capacity-per-unit-volume fuel is a gas which is employed at a relatively high pressure or which generates relatively more units of heat per unit volume at a standard temperature and pressure, and the low-heat-generating-capacity-per-unit-volume fuel is a gas which is employed at a relatively low pressure or which generates relatively less units of heat per unit volume at a standard temperature and pressure. Propane is referred to as an example of a conventionally employed high-heat-generating-capacity-per-unitvolume fuel and natural gas is referred to as an example of a conventionally employed low-heat-generatingcapacity-per-unit-volume fuel.

The burner apparatus can be employed in a wide variety of systems and applications and any fuel control device (not shown) suitable for any of such systems and applications can be connected to the input facilities 1 l to operate the burner apparatus. One example of a suitable fuel control device is the plural rate fuel control device disclosed in U.S. Pat. application Ser. No.

98,246 by Jay R. Katchka and Henry C. Braucksiek filed on Dec. 15, 1970.

The burner member has an outer tubular section 12, an intermediate tubular section 14 and a inner tubular'section 16, all coaxial and which have upper ends suitable secured together while lower flanged portions 18 and 20 of the respective tubular sections 14 and 16 are secured to the lower end of the outer tubular section 12 to form coaxial annular outer and inner chambers 22 and 24 respectively. The intermediate tubular section 14 forms a wall between the chambers 22 and 24 with a plurality of circumferentically spaced and outward-facing burner ports 48 which are aligned or radially basically concentric with respective circumferentially spaced and outward-facing burner ports 50 in the outer tubular second 12. Exact radial center line alignment of the ports48 and 50 is not required, only sufficient alignment to ensure that a substantial portion of the propane gas issuing from the ports 48 at a high rate of operation passes freely through the ports 50. The burner ports 48 are relatively smaller than the burner ports 50 and have a size capable of sustaining suitable flames from the ports 50 when propane gas is supplied to the inner chamber'24 while the burner ports 50 have a size capable of sustaining suitable flames when natural gas is supplied to the outer chamber22. I I

' Theinput-facilities 11 include a bevelled input opening 26 .in the intermediate tubular section 14 and an input opening 28 in the outer tubular section '12. The opening 26 is aligned with the opening 28. A fitting member or nipple'30 is suitable secured within the opening 28 of the outer tubular section 12 and has a threaded portion 32 which mates with a threaded portion 34 of a fitting member 36 which has a supply passageway 38. A reversible tubular member 40 has a ridge portion 42 formed at one end for being secured between the outward end of the fitting member 30 and an inward formed flange 44 of the fitting member 36.

l The other end 46 of the tubular member 40 is tapered such that it is fitted with the bevelled opening 26 when installed between the fitting members 30 and 36 as shown in FIG. 1. The tubular member 40 has a diameter designed to easily fit within the passageway 38 as shown in F1G. 2 for allowing communication between the passageway 38 and the chamber 22 when installed as shown in FIG. 2.

The inner tubular section 16 has a dimplied portion 52 with a burner port 54 directed inwardly and upwardly from the inner chamber 24. A bottom plate 56 secured to the burner member 10 has a plurality of circularly disposed openings 58 and a central opening 60 within which a tubular support 62 is suitably mounted. The upper end of the tubular support 62 is slotted and has a dimpled portion 64 which mates with a grooved portion 66 of the flame sensing element 68 for supporting the element 68'so that a flame extending from the port 54 impinges upon the element 68. The flame sensing element 68 is any suitable thermo-responsive device, such as a shielded thermocouple.

An upward flaring flame spreader 72 disposed in the path of burning streams of fuel extending horizontally from the burner ports 50 is attached by legs 76 to the outer tubular section 12. An upper flame spreader 78 disposed above the ports 50 has spokes 80 connected to a collar 82 which is secured to the outer tubular section 12. A frusto-conical flame shield 84 is connected hence produce suitable flames from the burner ports 4 by outward bent tabs 86 extending through openings 88 between the spokes of the flame spreader 78. A spaced top 92 bent horizontally from a leg extending upward from the shield 84 is secured by inward bent tabs 94 on legs 96 extending from the shield 84.

In operation of the burner apparatus of FIGS. 1 and 2 with propane, the tubular member 40 is inserted between the fitting members 30'and 36 as shown in FIG. 1 to secure the'tapered end 46 in the bevelled opening 26 to provide communication between the supply passageway 38 to the inner chamber 24. 'Propane gas passes from the supply passageway 38 through the member 40, the inner chamber 24 and out from the burner ports 48 to produce streams of propane gas which pass through the outer chamber 22 and the outer ports 50 to sustain flames from the ports 50. The ports 48 are designed for operation by propane gas and 50. Since ridge 42 of the tubular member 40 is tightly secured to the flanged portion of the fitting member 36 and the tapered end 46 of the tubular member 40 is tightly secured in the bevelled opening 26, the tubular member40 communicates between the supply passageway 38 and the inner chamber 24 to the exclusion of the outer chamber 22 and substantially no propane gas passes from the supply passageway 38 to the outer chamber 22 except through the ports 48.

At a high rate of operation propane gas issuing from the inner ports 48 passes freely through the larger outer ports 50 and is mixed with secondary air for combustion due to its relatively high velocity in hitting the flame spreader 72.

As shown in F1G.'2, for operation with natural gas the tubular member-40 is reversed to extend into the supply passageway 38 and allow communication from the passageway 38 to both of the chambers 22 and 24. Since the burner ports 50 are designed-for natural gas operation, natural gas from the supply passageway 38 through the tubular member 40, the opening 28 and the outer chamber 22 sustains suitable flames from the ports 50. Since natural gas is normally supplied at a lower pressure than propane, the velocity of natural gas from the ports 50 at a high rate of operation is much lower than the velocity of propane gas. However, the lower velocity is adequate to produce the required secondary air mix for the lower Btu per cubic foot content natural gas.

In operation with either natural gas or propane gas,

I fuel from the inner chamber 24 exits from the burner port 54 to sustain aflame impinging upon the flame sensing element 68. The spacing of the cover 92 by the legs 90 and 96 and the openings 58 in the bottom plate 56 provide adequate air for the flame from the burner port 54.

As an example, natural gas having a fuel content of about 1,000 Btu per cubic foot with a specific gravity relative to air of 0.64 and delivered to a single outer port 50 having a size of 0.038 inches in diameter at a pressure of 4 inches of water column would produce approximately 3,000 Btu per hour of heat in a flame from the single outer port. Propane gas having a fuel content of about 2,500 Btu per cubic foot with a spec fic gravity of 1.53 and applied to a single inner burner port 48 having a size of 0.021 inches in diameter at a pressure of 11 inches of water column would produce approximately 3,140 Btu per hour of heat in a flame from the single inner port.

FIGS. 3 and 4 illustrate a modification of the input facilities for selectively applying gas to the chambers 22 and 24 of the burner apparatus shown in FIGS. 1 and 2. An internally threaded fitting 203 is suitably attached to an input opening 226 of the intermediate tubular section 14. A tube 205 has a ridge 207 formed at one end which is suitably secured to an opening 228 in the outer tubular section 12. The tube 205 is suitably secured at its other end to an outside circumference of a gas selecting housing 209 while a tube 211 threaded at both ends is secured between the fitting 202 and a threaded opening of an inner passageway 213 in the gas selecting housing 209. A supply passage 238 communicates to the inner passageway 213 which communicates through the tube 211 into the inner chamber 24. As shown in FIG. 3, a reversable member 240 has a threaded plug portion 219 which is secured into another threaded opening 221 of the passageway 213 when the supply passageway 238 is connected to a propane source to exclude communication from the supply passageway 238 to the outer chamber 22 except through the ports 48. As shown in FIG. 6, the reversable member 240 has a threaded cap portion 223 which is secured to a threaded outer portion 225 of the housing 209 when natural gas is to be supplied to the supply passageway 238. The cap portion 223 provides an opening or passage 227 communicating from the inner passageway 213 to outer passageways 229 which are circularly disposed about the inner passageway 213 to communicate with the space between the tubes 205 and 211 and the outer chamber 22. Thus, the reversable member 240 is alternately positionable to adapt the burner apparatus for operation by propane or natural gas.

FIGS. 5 and 6 show a modification of the fuel selection facilities connected to the tubes 205 and 211 of FIGS. 3 and 4. The inner tube 211 has an outwardly flared portion 303 connecting to a enlarged portion 305 which is joined with the inside circumference of the outer tube 205. A threaded fitting member 307 mates with a threaded portion 309 of the enlarged portion 305 and surrounds a supply tube 313 having a sup-' ply passageway 338 and an outwardly flared end 315 which is engaged by the end of the fitting member 307 to tightly secure a reversable member 340 between the flared end 315 and the outwardly flared portion 303. As illustrated in FIG. 7, the reversable member 340 is positioned for use with propane and has a long tapered portion 321 which is adapted to completely cover openings 323 in the flared portion 303 of the tube 211 to exclude direct communication from the supply passageway 338 to the space between the tube 205 and 211. The other end of the reversable member 340 has a short tapered end 325 for engaging the flared end 315 of the supply tube 313 with a passageway 329 through the member 340 communicating between the supply passageway 338 and the tube 211. As illustrated in FIG. 8 when the reversable member 340 is reversed to adapt the burner for operation with natural gas, the long tapered portion 321 is engaged by the flared portion 315 of the supply tube 313 and the short tapered portion 325 engages the flared portion 303 of the tube 211 leaving the holes 323 exposed through a bevelled opening 327 to the passageway 329 in the reversable member 340. Thus the reversible member 340 is alternately positionable to convert the burner apparatus for operation by either propane or natural gas.

Since many variations, modifications, and changes in detail may be made to the present embodiments, it is What is claimed is: 1. A burner selectively adaptable for operation by a first fuel and a second fuel comprising a burner member containing a first chamber and a second chamber with a wall between the first and second chambers,

input means for communicating from a supply passageway to the first and second chambers,

said input means being capable of selectively communicating from the supply passageway to the first chamber,

said burner member having a first burner port from the first chamber and a second burner port in the wall exiting into the first chamber from the second chamber,

said first burner port being capable of producing streams of the first fuel for sustaining a flame, and

said second burner port being capable of producing streams of the second fuel from the first burner port, for sustaining a flame.

2. A burner as claimed in claim 1 wherein the second burner port is aligned with the first burner port.

3. A burner as claimed in claim 1 wherein said input means communicates to the second chamber when the burner is adapted for operation by either the first fuel or the second fuel. I I

4. A burner as claimed in claim 1 wherein the burner member is annular,

the first and second chambers are annular and coaxial,

the wall between the first and second chamber is annular,

there are a plurality of first burner ports spaced circumferentially and exiting from the first chamber, and

there are a plurality of second burner ports in the wall spaced circumferentially and exiting into the first chamber from the second chamber.

5. A burner as claimed in claim 4 wherein each of the second burner ports is aligned with a respective first burner port.

6. A burner as claimed in claim 1 wherein the input means includes a first opening through the wall,

a second opening into the first chamber aligned with the first opening, and

selective means for extending through the second opening to communicate from the supply passageway to the first opening to the exclusion of the first chamber.

7. A burner as claimed in claim 6 wherein the selective means includes reversible means for selectively communicating in a first position with both the first and second openings and in a second position with the first opening to the exclusion of the second opening.

8. A burner as claimed in claim 7 wherein the selective means includes threaded means for securing the reversible means.

9. A burner as claimed in claim 6 wherein the selective means includes a first fitting means secured to the second opening and having a threaded portion, a

a second fitting means having a threaded portion mating with the threaded portion of the first fitting means and communicating with the supply passageway,

a reversible tubular member having a ridge toward one end adapted to be secured between the first and second fitting means,

said tubular member adapted at its other end to extend through the first fitting member and the first chamber and to be fitted with the first opening to the exclusion of the first chamber.

10. A burner as defined in claim 9 wherein the first opening is bevelled and the other end of the tubular member is tapered to mate with the bevelled opening.

11. A burner selectively adaptable for operation by a first gaseous fuel and a second gaseous fuel where the second gaseous fuel has a higher heat-generating capacity per unit volume than the first gaseous fuel comprising a burner member containing a first chamber and a second chamber with a wall between the first and I second chambers,

said burner member having a first burner port from the first chamberand having a second burner port from the -second chamber,

said first burner port being capable of producing streams of the first fuel for sustaining a flame,

said second burner port being capable of producing streams of the second fuel for sustaining a flame,

said wall having a first opening between the first and second chambers said burner memberhaving a'second opening into the first chamber and aligned with the first opening, and A selective means for extending through the second opening to communicate from a supply passageway to the first opening to the exclusion of the first chamber.-

12. A burner as claimed in claim 11 wherein the selective means includes 7 reversible means for selectively communicating in a first position with both the first and second openings and in a second position with the first opening to the exclusion of the second opening, and

threaded means for securing the reversible means. 13. A burner apparatus selectively adaptable for operation by a first gaseous fuel and a second gaseous fuel comprising a burner member containing a first chamber and a second chamber; a flame sensing element; means for supporting the flame sensing element adjacent the burner member;

, said burner member having a first burner port capable of producing streams of the first fuel from the first chamber, a second burner port capable of producing streams of the second fuel from the second chamber and a third burner port capable of producing streams of both the first and second fuels from the second chamber, said first and second burner ports directed away from the flame sensing element; said third burner port directed toward the flame sensing element; and

input means having a first selective operating position for communicating from a supply passageway to both the first and second chambers and having a second selective operating position for communicating from the supply passageway to the second chamber to the exclusion of the first chamber.

14. A burner apparatus as claimed in claim 13 wherein the burner member has a wall between the first chamber and the second chamber, and

the second burner port is formed through the wall to exit into the first chamber from the second chamber.

15. A burner apparatus as claimed in claim 14 wherein the second burner port is aligned with the first burner port and is smaller than the first burner port.

16. A burner apparatus as claimed in claim 14 wherein the input means includes a first opening in the wall between the first and second chambers,

a second opening in the burner member aligned with the first opening,

means for extending through the second opening to communicate with the first opening,

said extending means including reversable means having a first position for communicating from a supply passageway to both the first and second openings and having a second position for communicating from the supply passageway to the first opening to theexclusion of the second chamber, and

thread means for selectively securing the reversable means in the first and second positions.

17. A burner selectively adaptable for operation by a first gaseous fuel and a second gaseous fuel comprising a burner member having an inner tubular section, an

intermediate tubular section and an outer tubular section, all coaxial and joined together to form coaxial inner and outer annular chambers,

said burner member having a plurality of first burner ports circumferencially spaced in the outer tubular section exiting outward from the outer chamber, said housing having a plurality of second burner ports I formed in the intermediate tubular section exiting from the inner chamber to the outer chamber, each of said second burner ports aligned with a respective first burner port, input means for communicating from a supply passageway to the inner and outer chambers, and

said input means including selective means for selectively communicating with the inner chamber to the exclusion of the outer chamber.

18. A burner apparatus as claimed in claim 17 wherein the input means includes a first opening through the intermediate tubular section and a second opening through the outer tubular section and aligned with the first opening,

said selective means includes means for extending through the second opening to communicate with the first opening to the exclusion of the outer chamber.

19. A burner apparatus as claimed in claim 18 wherein there is included a flame sensing element,

there is included means for supporting the flame sensing element within the inner tubular section, and

the inner tubular section has a burner port from the inner chamber directed toward the flame sensing element.

20. A burner selectively adaptable for operation by a first gaseous fuel and a second gaseous fuel where the second gaseous fuel has a higher heat-generating capacity per unit volume then the first gaseous fuel comprising a burner member having an inner tubular section an intermediate tubular section and an outer tubular section, all coaxial and joined together to form coaxial inner and outer annular chambers, said burner member having a plurality of first burner ports circumferentially spaced in the outer tubular section exiting outward from the outer chamber,

said burner member having a plurality of second burner ports formed in the intermediate tubular section exiting from the inner chamber to the outer chamber, each of said second burner ports being smaller and aligned with a respective first burner port,

a flame sensing element,

means for supporting the flame sensing element along the axis of the burner member,

said burner member having an third burner port in the inner tubular section directed toward the flame sensing element from the inner chamber,

said burner member having a first input opening in the intermediate tubular section and a second input opening in the outer tubular section and aligned with the first input opening,

a first fitting means secured to the second input opening and having a threaded portion,

a second fitting means having a threaded portion mating with the threaded portion of the first fitting means and communicating with a'supply passageway,

a reversible tubular member having a ridge toward one end adapted to be secured between the first and second fitting means, and

said tubular member adapted at its other end to extend through the first fitting member and the outer chamber and to be fitted with the first opening to the exclusion of the outer chamber. 

1. A burner selectively adaptable for operation by a first fuel and a second fuel comprising a burner member containing a first chamber and a second chamber with a wall between the first and second chambers, input means for communicating from a supply passageway to the first and second chambers, said input means being capable of selectively communicating from the supply passageway to the first chamber, said burner member having a first burner port from the first chamber and a second burner port in the wall exiting into the first chamber from the second chamber, said first burner port being capable of producing streams of the first fuel for sustaining a flame, and said second burner port being capable of producing streams of the second fuel from the first burner port, for sustaining a flame.
 2. A burner as claimed in claim 1 wherein the second burner port is aligned with the first burner port.
 3. A burner as claimed in claim 1 wherein said input means communicates to the second chamber when the burner is adapted for operation by either the first fuel or the second fuel.
 4. A burner as claimed in claim 1 wherein the burner member is annular, the first and second chambers are annular and coaxial, the wall between the first and second chamber is annular, there are a plurality of first burner ports spaced circumferentially and exiting from the first chamber, and there are a plurality of second burner ports in the wall spaced circumferentially and exiting into the first chamber from the second chamber.
 5. A burner as claimed in claim 4 wherein each of the second burner ports is aligned with a respective first burner port.
 6. A burner as claimed in claim 1 wherein the input means includes a first opening through the wall, a second opening into the first chamber aligned with the first opening, and selective means for extending through the second opening to communicate from the supply passageway to the first opening to the exclusion of the first chamber.
 7. A burner as claimed in claim 6 wherein the selective means includes reversible means for selectively communicating in a first position with both the first and second openings and in a second position with the first opening to the exclusion of the second opening.
 8. A burner as claimed in claim 7 wherein the selective means includes threaded means for securing the reversible means.
 9. A burner as claimed in claim 6 wherein the selective means includes a first fitting means secured to the second opening and having a threaded portion, a second fitting means having a threaded portion mating with the threaded portion of the first fitting means and communicating with the supply passageway, a reversible tubular member having a ridge toward one end adapted to be secured between the first and second fitting means, said tubular member adapted at its other end to extend through the first fitting member and the first chamber and to be fitted with the first opening to the exclusion of the first chamber.
 10. A burner as defined in claim 9 wherein the first opening is bevelled and the other end of the tubular member is tapered to mate with the bevelled opening.
 11. A burner selectively adaptable for operation by a first gaseous fuel and a second gaseous fuel where the second gaseous fuel has a higher heat-generating capacity per unit volume than the first gaseous fuel comprising a burner member containing a first chamber and a second chamber with a wall between the first and second chambers, said burner member having a first burner port from the first chamber and having a second burner port from the second chamber, said first burner port being capable of producing streams of the first fuel for sustaining a flame, said second burner port being capable of producing streams of the second fuel for sustaining a flame, said wall having a first opening between the first and second chambers said burner member having a second opening into the first chamber and aligned with the first opening, and selective means for extending through the second opening to communicate from a supply passageway to the first opening to the exclusion of the first chamber.
 12. A burner as claimed in claim 11 wherein the selective means includes reversible means for selectively communicating in a first position with both the first and second openings and in a second position with the first opening to the exclusion of the second opening, and threaded means for securing the reversible means.
 13. A burner apparatus selectively adaptable for operation by a first gaseous fuel and a second gaseous fuel comprising a burner member containing a first chamber and a second chamber; a flame sensing element; means for supporting the flame sensing element adjacent the burner member; said burner member having a first burner port capable of producing streams of the first fuel from the first chamber, a second burner port capable of producing streams of the second fuel from the second chamber and a third burner port capable of producing streams of both the first and second fuels from the second chamber, said first and second burner ports directed away from the flame sensing element; said third burner port directed toward the flame sensing element; and input means having a first selective operating position for communicating from a supply passageway to both the first and second chambers and having a second selective operating position for communicating from the supply passageway to the second chamber to the exclusion of the first chamber.
 14. A burner apparatus as claimed in claim 13 wherein the burner member has a wall between the first chamber and the second chamber, and the second burner port is formed through the wall to exit into the first chamber from the second chamber.
 15. A burner apparatus as claimed in claim 14 wherein the second burner port is aligned with the first burner port and is smaller than the first burner port.
 16. A burner apparatus as claimed in claim 14 wherein the input means includes a first opening in the wall between the first and second chambers, a second opening in the burner member aligned with the first opening, Means for extending through the second opening to communicate with the first opening, said extending means including reversable means having a first position for communicating from a supply passageway to both the first and second openings and having a second position for communicating from the supply passageway to the first opening to the exclusion of the second chamber, and thread means for selectively securing the reversable means in the first and second positions.
 17. A burner selectively adaptable for operation by a first gaseous fuel and a second gaseous fuel comprising a burner member having an inner tubular section, an intermediate tubular section and an outer tubular section, all coaxial and joined together to form coaxial inner and outer annular chambers, said burner member having a plurality of first burner ports circumferencially spaced in the outer tubular section exiting outward from the outer chamber, said housing having a plurality of second burner ports formed in the intermediate tubular section exiting from the inner chamber to the outer chamber, each of said second burner ports aligned with a respective first burner port, input means for communicating from a supply passageway to the inner and outer chambers, and said input means including selective means for selectively communicating with the inner chamber to the exclusion of the outer chamber.
 18. A burner apparatus as claimed in claim 17 wherein the input means includes a first opening through the intermediate tubular section and a second opening through the outer tubular section and aligned with the first opening, said selective means includes means for extending through the second opening to communicate with the first opening to the exclusion of the outer chamber.
 19. A burner apparatus as claimed in claim 18 wherein there is included a flame sensing element, there is included means for supporting the flame sensing element within the inner tubular section, and the inner tubular section has a burner port from the inner chamber directed toward the flame sensing element.
 20. A burner selectively adaptable for operation by a first gaseous fuel and a second gaseous fuel where the second gaseous fuel has a higher heat-generating capacity per unit volume then the first gaseous fuel comprising a burner member having an inner tubular section an intermediate tubular section and an outer tubular section, all coaxial and joined together to form coaxial inner and outer annular chambers, said burner member having a plurality of first burner ports circumferentially spaced in the outer tubular section exiting outward from the outer chamber, said burner member having a plurality of second burner ports formed in the intermediate tubular section exiting from the inner chamber to the outer chamber, each of said second burner ports being smaller and aligned with a respective first burner port, a flame sensing element, means for supporting the flame sensing element along the axis of the burner member, said burner member having an third burner port in the inner tubular section directed toward the flame sensing element from the inner chamber, said burner member having a first input opening in the intermediate tubular section and a second input opening in the outer tubular section and aligned with the first input opening, a first fitting means secured to the second input opening and having a threaded portion, a second fitting means having a threaded portion mating with the threaded portion of the first fitting means and communicating with a supply passageway, a reversible tubular member having a ridge toward one end adapted to be secured between the first and second fitting means, and said tubular member adapted at its other end to extend through the first fitting member and the outer chamber and to be fitted with the first opening to the exclusion of the outer chamber. 